1. Field of the Invention
The present invention relates to a technique for correcting hand movement during image pickup operation.
2. Description of the Related Art
As a hand movement correction method for correcting hand movement occurring in a process of taking still or moving pictures by making use of an image pickup apparatus, there is known a method (shift lens system) that uses a shift lens serving as a kind of an optical hand movement correction means. The shift lens system is a hand movement correction system that utilizes light refraction. That is, the shift lens system detects the movement of an image pickup apparatus by making use of an angular speed sensor or the like provided therein and drives a shift lens in the direction canceling the movement (positional shift amount of light with respect to an image pickup device) detected by the angular speed sensor during a time period between the start and end of exposure operation to correct the optical axis of the lens, whereby the light reaches an original target point. Thus, the correction range in the shift lens system is restricted by the movable range of the shift lens, so that correction needs to be made such that the correction range falls within the movable range of the shift lens.
In the case where the detected movement of the image pickup apparatus is not due to unintentional hand movement but a photographer's intentional hand movement (pan/tilt), the movement may far exceed the correction range, generating strong unnatural feeling (large shake) in the finder image. As a method for reducing the strong unnatural feeling, there is known a technique that controls a correction gain by performing initialization of an input value from the angular speed sensor, position output value after integration, and integration calculation so as to temporarily restrict the correction operation (refer to, e.g., Patent Document 1: Jpn. Pat. Appln. Laid-Open Publication No. 2001-209084).
As described above, in the technique disclosed in Patent Document 1, in order to restore the original correction operation, correction control such as temporarily stopping the hand movement correction or reducing the correction gain according to a predetermined time constant is required, and such correction control requires a certain time. If still image pickup operation is performed during the correction control, desired correction is hardly applied to image data, with the result that obtained image is blurred.